1. Field of the Invention
The present invention relates to a receiving apparatus, a receiving method, and a program, in particular, for example, a receiving apparatus, a receiving method, and a program which are suitable for use in the case of receiving terrestrial digital broadcasting in the United States.
2. Description of the Related Art
In television broadcasting, channels (frequencies) for broadcast signals vary by region. Therefore, a channel that is receivable in a given region may not be receivable in another region in some cases.
On the other hand, for example, in the case of compact, lightweight portable television receivers that are mounted in an automobile or carried by the user, it is highly likely that the location of their use, that is, the location of reception is changed frequently.
Some of portable television receivers have a function of acquiring positional information on the current location, and holds receive channel lists corresponding to individual reception regions in advance, identify a reception region to which the current location indicated by the acquired positional information belongs, and acquires a receive channel list corresponding to the identified reception region. In this regard, a receive channel list is a list describing only channels that are receivable in a corresponding reception region. The receive channel list is used in the case of, for example, switching channels only between channels included in the receive channel list, in response to a channel up/down operation made from the user.
As a function for acquiring positional information on the current location, for example, there is a method of using a GPS (Global Positioning System), or a method of exploiting positional information obtained by a navigation system (see, for example, Japanese Unexamined Patent Application Publication No. 7-284030).
As described above, the method of acquiring a receive channel list corresponding to the current location is effective in the case of, for example, receiving terrestrial digital broadcasting in Japan. This is because in the case of terrestrial digital broadcasting in Japan, normally, reception regions are set on a prefecture-by-prefecture basis, and a reception region can be uniquely identified on the basis of acquired position information on the current location.
However, the above-described method is not necessarily appropriate in the case of receiving terrestrial digital broadcasting in the United States. This is because in the case of terrestrial digital broadcasting in the United States, there is no reference (for example, the prefecture-by-prefecture basis in Japan) as to how to set reception regions, and hence it is not possible to uniquely identify a reception region from acquired positional information on the current location, and moreover, there is an overlap in reception region.
Now, a description will be given of terrestrial digital broadcasting in the United States.
FIG. 1 shows frequency bands used for terrestrial digital broadcasting in the United States. That is, a broadcast is transmitted by using the VHF band from CH(channel) 2 to CH13, and is transmitted by using UHF from CH14 to CH51.
As described above, when receiving terrestrial digital broadcasting in the United States, it is not possible to acquire a receive channel list in accordance with the current location. Accordingly, for example, as shown in FIG. 2, it is necessary to select all channels from CH2 to CH51 sequentially to determine success/failure of reception (hereinafter, referred to as all-channel scan), and create a receive channel list on the basis of the determination results. Since this all-channel scan determines success/failure of reception on each channel, it takes quite a long time to finish the all-channel scan, forcing inconvenience on the user.
FIG. 3 shows an example of a community equivalent to the above-described reception region in the United States. One or more broadcasting stations (hereinafter, also referred to as stations) belong to the community. However, this does not mean that broadcast signals from all the broadcasting stations belonging to the community can be received throughout the entire area of the community.
That is, of all the broadcasting stations belonging to the community, the coverage area of a broadcasting station with the largest coverage area (receivable range) coincides with the range of the community. The coverage area of each broadcasting station is not necessarily circular or elliptical, but may have directivity with respect to a predetermined direction in some cases.
For example, three stations, A, B, and C, belong to a community C1, of which the station A with the largest coverage area serves as a representative station. The coverage area of the station B is smaller than that of the station A. The coverage area of the station C has directivity.